Empty component hierarchy sometimes

This is probably more suited to a mailing list / forum, but the mail list comment appeared to point me here.
I have a unit test which tests a dialog. I am using cacio-tta to enable it to run headless. This seems to run reliably in Windows and much of the time in Linux ... but maybe half of the time in linux the component lookup fails. When it fails, the component hierarchy is empty.

The failure looks as follows (I am running under junit4 with the CacioTestRunner)

```
org.assertj.swing.exception.ComponentLookupException: Unable to find component using matcher org.assertj.swing.core.NameMatcher[name='amendmentReasonLabel', type=javax.swing.JLabel, requireShowing=true].

Component hierarchy:
com.ccm.backtest.fund.AdhocTradeEntryDlg[name='dialog1', title='Amend Trade', enabled=true, modal=true, visible=true, showing=true]

at org.assertj.swing.core.BasicComponentFinder.componentNotFound(BasicComponentFinder.java:290)
at org.assertj.swing.core.BasicComponentFinder.find(BasicComponentFinder.java:275)
at org.assertj.swing.core.BasicComponentFinder.find(BasicComponentFinder.java:268)
at org.assertj.swing.core.BasicComponentFinder.findByName(BasicComponentFinder.java:203)
at org.assertj.swing.fixture.AbstractContainerFixture.findByName(AbstractContainerFixture.java:622)
at org.assertj.swing.fixture.AbstractContainerFixture.label(AbstractContainerFixture.java:291)
at com.ccm.backtest.fund.AdhocTradeEntryDlgTest.testAmendETFuture(AdhocTradeEntryDlgTest.java:103)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)

```

The relevant test code that is failing is...

``` Java
@Test
public void testAmendETFuture()
{
MockAssetFactory assetFactory = new MockAssetFactory();
Date today = java.sql.Date.valueOf("2015-01-02");
ETFuture future = new ETFuture(today, assetFactory.get("FTH16"), 2, Side.SELL, 1.234, today);
future.setBrokerageFee(2.34, assetFactory.get("CAD"));
future.setClearingFee(5.67, assetFactory.get("EUR"));
setupDialog("book", future, assetFactory, AdhocTradeEntryDlg.Operation.AMEND);

dialogFixture.label("amendmentReasonLabel").requireVisible();
```

where the setupDialog() code looks like:

``` Java
private void setupDialog(String book, Transaction trade, IAssetFactory assetFactory, AdhocTradeEntryDlg.Operation operation)
{
dialog = GuiActionRunner.execute(new GuiQuery()
{
protected AdhocTradeEntryDlg executeInEDT()
{
AdhocTradeEntryDlg dlg = new AdhocTradeEntryDlg(book, trade, assetFactory, operation);
dlg.pack();
return dlg;
}
});

// IMPORTANT: note the call to 'robot()'
// we must use the Robot from AssertJSwingJUnitTestCase
dialogFixture = new DialogFixture(robot(), dialog);
dialogFixture.show(new Dimension(800, 800));
}
```

I added the pack() call which makes the issue appear less often ... and so I am guessing there is a synchronisation issue at play here. The other interesting thing is that there are 4 almost identical tests in this test case - they all call setupDialog (it's not in onSetUp because there is more than one flavor as I require different tests to call different constructors for the object).
What would be a good way to debug this?

Ian